[1]
Aitchison, J. 1981. Language change: progress or decay?. Fontana Paperbacks.
[2]
Awbery, G. 1978. Y tafodieithoedd Cymraeg. Cyflwyno’r iaith lenyddol: an introduction to the literary forms of the Welsh language. (1978), 193–203.
[3]
Awbery, G.M. 1991. Cymraeg Sir Benfro. Gwasg Carreg Gwalch.
[4]
Ball, M.J. 1988. The Use of Welsh: a contribution to socioloinguistics. Multilingual Matters.
[5]
Ball, M.J. and Fife, J. 1993. The Celtic languages. Routledge.
[6]
Bowen, G. 1976. Y traddodiad rhyddiaith yn yr ugeinfed ganrif: darlithiau Dewi Sant. Gwasg Gomer.
[7]
Cameron, K. 1961. English place-names. Batsford.
[8]
Carr, G. 2011. Hen enwau o Arfon, Llŷn ac Eifionydd. Gwasg y Bwythyn.
[9]
Charles, B.G. 1938. Non-Celtic place names in Wales. London Mediaeval Studies.
[10]
Crystal, D. 1987. The Cambridge encyclopedia of language. Cambridge University Press.
[11]
Crystal, D. and ebrary, Inc 2002. Language death. Cambridge University Press.
[12]
Davies, C. 2000. Adfeilion Babel: agweddau ar syniadaeth ieithyddol y ddeunawfed ganrif. Gwasg Prifysgol Cymru.
[13]
Davies, E. and University of Wales 1967. Rhestr o enwau lleoedd: A gazetteer of Welsh place-names. Gwasg Prifysgol Cymru.
[14]
Davies, J. 1993. The Welsh language. University of Wales Press.
[15]
Evans, D.S. 1951. Gramadeg Cymraeg Canol. Gwasg Prifysgol Cymru.
[16]
Fynes-Clinton, O.H. 1913. The Welsh vocabulary of the Bangor district. printed for the author by Horace Hart at the Oxford University Press.
[17]
Griffiths, B. et al. 1995. The Welsh Academy English-Welsh dictionary: Geiriadur yr Academi. Gwasg Prifysgol Cymru, University of Wales Press.
[18]
Gwyndaf, R. 1961. Aur dan y rhedyn. Taliesin. 43, (1961), 55–61.
[19]
Haycock, M. ‘Jones y Dwyrain’. Traethodydd: cylchgrawn chwarterol at wasanaeth Crefydd, Diwinyddiaeth, Athroniaeth a Llenyddiaeth.
[20]
Jackson, K.H. 1953. Language and history in early Britain: a chronological survey of the Brittonic languages, 1st to 12th c. A.D. Edinburgh University Press.
[21]
Jenkins, G.H. 1998. Iaith carreg fy aelwyd: iaith a chymuned yn y bedwaredd ganrif ar bymtheg. Gwasg Prifysgol Cymru.
[22]
Jenkins, G.H. 1997. Y Gymraeg yn ei disgleirdeb: yr iaith Gymraeg cyn y Chwyldro Diwydiannol. Gwasg Prifysgol Cymru.
[23]
Jones, B.L. 1987. Blas ar Iaith Llŷn ac Eifionydd. Gwasg Carreg Gwalch.
[24]
Jones, B.L. 1991. Enwau: rhai o ysgrifau Ditectif Geiriau yn y Western Mail. Gwasg Carreg Gwalch.
[25]
Jones, B.L. 1992. Yn ei elfen. Gwasg Carreg Gwalch.
[26]
Jones, B.L. and Griffiths, B. 1983. Iaith Sir Fôn. Llygad yr Haul.
[27]
Jones, C. and Thorne, D.A. 1992. Dyfed: blas ar ei thafodieithoedd. Gwasg Gomer.
[28]
Jones, M. 1994. A Tale of Two Welsh Dialects: standardization in modern spoken Welsh. The changing voices of Europe: social and political change and their linguistic repercussions, past, present and future. (1994).
[29]
Jones, M.D. 1972. Termau iaith a llên. Gwasg Gomer.
[30]
Jones, R.E. 1962. Casgiad o dermau chwarel. Bulletin of the Board of Celtic Studies. 20, (1962).
[31]
Jones, R.O. 1997. ‘Hir oes i’r iaith’: agweddau ar hanes y Gymraeg a’r gymdeithas. Gomer.
[32]
Lewis, H. 1983. Datblygiad yr iaith Gymraeg: gan Henry Lewis. Gwasg Prifysgol Cymru.
[33]
Lewis, H. 1943. Yr elfen Ladin yn yr iaith Gymraeg. Gwasg Prifysgol Cymru.
[34]
Lloyd-Jones, J. 1928. Enwau Lleoedd Sir Gaernarfon: gan J. Lloyd-Jones. Gwasg Prifysgol Cymru.
[35]
Llyfrgell Adnoddau y Coleg Cymraeg Cenedlaethol | Y Traddodiad Rhyddiaith yn yr Ugeinfed Ganrif – Geraint Bowen (gol.): https://llyfrgell.porth.ac.uk/media/y-traddodiad-rhyddiaith-yn-yr-ugeinfed-ganrif-geraint-bowen-gol.
[36]
MacAulay, D. 1992. The Celtic languages. Cambridge University Press.
[37]
McMahon, A.M.S. 1994. Understanding language change. Cambridge University Press.
[38]
Morgan, T.J. and Morgan, P. 1985. Welsh surnames. University of Wales Press.
[39]
Morris-Jones, J. 1913. A Welsh grammar: historical and comparative : phonology and accidence. Clarendon Press.
[40]
Owen, H.W. and Morgan, R. 2007. Dictionary of the Place-Names of Wales. Y Lolfa.
[41]
Parry-Williams, T.H. 1923. The English element in Welsh: a study of English loan-words in Welsh. Hon. Society of Cymmrodorion.
[42]
Pedersen, H. 1962. The discovery of language: linguistic science in the nineteenth century. Indiana University Press.
[43]
Phillips, V.H. 1981. Iaith lafar sir Drefaldwyn. Bro’r Eisteddfod: (cyflwyniad i Faldwyn a’i chyffiniau). (1981).
[44]
Richards, M. and Jones, B.L. 1998. Enwau tir a gwlad. Gwasg Gwynedd.
[45]
Robins, R.H. 1967. A short history of linguistics. Longman.
[46]
The National Library of Wales - Full Catalogue: http://cat.llgc.org.uk/cgi-bin/gw/chameleon?lng=en&search=KEYWORD&function=CARDSCR&u1=12101&t1=001070781.
[47]
Thomas, A.R. 1973. The linguistic geography of Wales: a contribution to Welsh dialectology. University of Wales Press [for] the Board of Celtic Studies.
[48]
Thomas, B. and Thomas, P.W. 1989. Cymraeg, Cymrâg, Cymrêg,...cyflwyno’r tafodieithoedd. Gwasg Taf.
[49]
Thomas, P.W. 1996. Gramadeg y Gymraeg. Gwasg Prifysgol Cymru.
[50]
Thomas, R.J. 1938. Enwau afonydd a nentydd Cymru. Gwasg Prifysgol Cymru.
[51]
Thorne, D.A. 1985. Cyflwyniad i astudio’r iaith Gymraeg. Cyhoeddwyd ar ran Bwrdd Gwybodau Celtaidd Prifysgol Cymru [by] Gwasg Prifysgol Cymru.
[52]
Watkins, T.A. 1961. Ieithyddiaeth: agweddau ar astudio iaith. Gwasg Prifysgol Cymru.
[53]
Wiliam, M. 1990. Blas ar iaith Blaenau’r Cymoedd. Gwasg Carreg Gwalch.
[54]
Williams, C.H. and University of Wales 2000. Language revitalization: policy and planning in Wales. University of Wales Press.
[55]
Williams, I. 1962. Enwau lleoedd. Gwasg y Brython.
[56]
Williams, J.E.C. and Hughes, M.B. 1988. Llyfryddiaeth yr iaith Gymraeg. Gwasg Prifysgol Cymru.
[57]
Williams, S.J. 1980. Elfennau gramadeg Cymraeg. Gwasg Prifysgol Cymru.